The electrical potentials generated by neurons, primary afferent fibers and glia cells, will be studied during seizure activity caused by toxic dose of penicillin and other epileptogenic procedures in spinal cord and cerebral cortex. The electrical properties of cells, extracellular potassium concentration, and the metabolic activity (oxidation of NADH) will be measured in situ. The following specific questions are asked: 1. Does K ion discharged from active neurons play a part either in the initiation of seizures, or in their maintenance and spread, once they begin? 2. Are clonic cell discharges synchronized by the action of extracellular current? 3. What protects a spinal gray matter from the occurrence of spreading depression? 4. Does penicillin have a direct toxic effect on cell membranes? 5. What is the relationship between cerebral and spinal seizure patterns? BIBLIOGRAPHIC REFERENCES: T. Pellmar and G. Somjen. Velocity of supraspinal input and conduction velocity of axons of spinal motoneurons. Brain Res. 120:179-183, 1977. S. Yamada, J. LaManna, B. Younts, M. Rosenthal and G. Somjen. Responses of oxidative metabolism and extracellular potassium to afferent stimulation of the cat spinal cord. Fed. Proc. 36:516, #1289, 1977.